SILVIS Lab, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, Wisconsin, 53706, USA.
Departments of Economics and Environmental Studies, Amherst College, P.O. Box 5000, Amherst, Massachusetts, 01002, USA.
Ecol Appl. 2018 Dec;28(8):1982-1997. doi: 10.1002/eap.1753. Epub 2018 Oct 15.
Forest fragmentation can lead to habitat reduction, edge increase, and exposure to disturbances. A key emerging policy to protect forests is payments for ecosystem services (PES), which offers compensation to landowners for environmental stewardship. Mexico was one of the first countries to implement a broad-scale PES program, enrolling over 2.3 Mha by 2010. However, Mexico's PES did not completely eliminate deforestation in enrolled parcels and could have increased incentives to hide deforestation in ways that increased fragmentation. We studied whether Mexican forests enrolled in the PES program had less forest fragmentation than those not enrolled, and whether the PES effects varied among forest types, among socioeconomic zones, or compared to the protected areas system. We analyzed forest cover maps from 2000 to 2012 to calculate forest fragmentation. We summarized fragmentation for different forest types and in four socioeconomic zones. We then used matching analysis to investigate the possible causal impacts of the PES on forests across Mexico and compared the effects of the PES program with that of protected areas. We found that the area covered by forest in Mexico decreased by 3.4% from 2000 to 2012, but there was 9.3% less forest core area. Change in forest cover was highest in the southern part of Mexico, and high-stature evergreen tropical forest lost the most core areas (-17%), while oak forest lost the least (-2%). Our matching analysis found that the PES program reduced both forest cover loss and forest fragmentation. Low-PES areas increased twice as much of the number of forest patches, forest edge, forest islets, and largest area of forest lost compared to high-PES areas. Compared to the protected areas system in Mexico, high-PES areas performed similarly in preventing fragmentation, but not as well as biosphere reserve core zones. We conclude that the PES was successful in slowing forest fragmentation at the regional and country level. However, the program could be improved by targeting areas where forest changes are more frequent, especially in southern Mexico. Fragmentation analyses should be implemented in other areas to monitor the outcomes of protection programs such as REDD+ and PES.
森林破碎化可能导致栖息地减少、边缘增加和暴露于干扰之中。保护森林的一个新兴关键政策是生态系统服务付费（PES），它为土地所有者的环境管理提供补偿。墨西哥是第一个实施大规模 PES 计划的国家之一，到 2010 年，该计划已覆盖了超过 230 万公顷的土地。然而，墨西哥的 PES 并没有完全消除已登记地块的森林砍伐，反而可能增加了以增加破碎化的方式隐藏森林砍伐的激励。我们研究了墨西哥 PES 计划所涵盖的森林是否比未登记的森林破碎化程度更低，以及 PES 的影响是否因森林类型、社会经济区或与保护区系统的比较而有所不同。我们分析了 2000 年至 2012 年的森林覆盖图，以计算森林破碎化。我们总结了不同森林类型和四个社会经济区的破碎化情况。然后，我们使用匹配分析来研究 PES 对墨西哥各地森林的可能因果影响，并将 PES 计划的效果与保护区的效果进行比较。我们发现，2000 年至 2012 年，墨西哥的森林覆盖面积减少了 3.4%，但森林核心区减少了 9.3%。森林覆盖变化最大的是墨西哥南部，高海拔常绿热带森林失去了最多的核心区（-17%），而栎树林失去的最少（-2%）。我们的匹配分析发现，PES 计划减少了森林覆盖损失和森林破碎化。与高 PES 地区相比，低 PES 地区的森林斑块、森林边缘、森林小岛和最大森林损失面积的数量增加了两倍。与墨西哥的保护区系统相比，高 PES 地区在防止破碎化方面表现相似，但不如生物圈保护区核心区。我们的结论是，PES 在区域和国家层面上成功地减缓了森林破碎化。然而，该计划可以通过针对森林变化更频繁的地区来改进，特别是在墨西哥南部。应该在其他地区实施破碎化分析，以监测 REDD+和 PES 等保护计划的结果。
